1. Field of the Invention
The invention concerns a gantry, in particular for a computed tomography apparatus of the type generally known from DE 196 47 626 A1.
2. Description of the Prior Art
In such gantries (in particular for computed tomography systems) with a single x-ray tube, the expansion of an x-ray beam (generated by the x-ray tube) with regard to the rotation of the gantry in the axial direction is primarily determined by two factors. First, the anode inclination angle α of the rotatable anode dish of the rotary anode assembly in the x-ray tube limits the maximum angle range that can be covered with sufficient power by the x-ray beam, so that an optimally large anode inclination angle is sought. Second, an anode inclination angle that is too large causes an increased variance of the effective size of the projections of the focal spot in the direction of the image, and can lead to substantial image blurring. Limits are therefore set as to the enlargement of the expansion of the x-ray beam in the axial direction. To increase the x-ray power (which is approximately proportional to the diameter of the anode dish of the x-ray tube), an enlargement of the anode dish would be desirable, but this would require a corresponding enlargement (and available space for such an enlargement) of many components.